(a) Field of the Invention
The present invention relates to a manufacturing method of a thin film transistor array panel for a display device.
(b) Description of the Related Art
At present, a liquid crystal display (“LCD”) is one of the most widely used flat panel displays. An LCD, which includes two panels having electrodes and a liquid crystal layer interposed therebetween, controls the transmittance of light passing through the liquid crystal layer by realigning liquid crystal molecules in the liquid crystal layer with voltages applied to the electrodes. Among these LCDs, the most commonly used one provides at least one electrode on each panel and includes thin film transistors (“TFTs”) switching the voltages applied to the electrodes.
Generally, a panel with TFTs (“TFT array panel”) includes, in addition to the TFTs, signal wires including gate lines transmitting scanning signals, data lines transmitting image signals, gate pads transmitting the scanning signals from external devices to the gate lines, and data pads transmitting the image signals from external devices to the data lines. The TFT array panel further includes pixel electrodes electrically connected to the TFTs and located in respective pixel areas defined by the intersections of the gate lines and the data lines.
In a reflective LCD or a transflective LCD, the pixel electrodes are made of a transparent conductive material such as indium tin oxide (“ITO”) and overlap signal wires to ensure aperture ratio of pixels. Also, an insulating layer made of organic insulating material with low dielectric constant is formed between the signal wires and the pixel electrodes to minimize the interference of the signals transferred through them.
Moreover, the pixel electrodes of the transflective LCD are made of using a reflective conductive material such as Al or Ag as well as ITO, and formed to have embossment for increasing the reflecting ratio of the pixel electrodes. The embossment of the reflecting film is formed by providing an organic insulating layer with unevenness under the pixel electrode.
However, adhesiveness between the organic insulating layer and the ITO film is deteriorated when forming the ITO film on the insulating layer made of the organic insulating material. To solve the problem the roughness of the surface of the organic insulating layer is increased by performing a plasma process before depositing the ITO film.
However, contact resistance of a contact exposing the wire to be connected to the pixel electrode is increased since the organic material is re-deposited on the wire in the contact during the plasma process.